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US 2013/0154637 A1Published application
Measurement of chemical equilibrium ratio using a magnetic resonance spectroscopy system
AssigneeGeneral Electric Company
InventorsAlbert Po-Fu Chen, Ralph Eugene Hurd
Life of this patent
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Abstract
The use of selective RF excitation is discussed. A spectrally selective, large tip angle RF pulse is used to detect a weak signal from a first chemical species. A non-selective, small tip angle pulse is used in measuring a signal from a second chemical species in exchange with the first chemical species. The acquired resonance data provides maybe used to measure the ratio of the spectrally distinct species in exchange.
Claims20
A method for measuring a ratio of two or more spectrally distinct chemical species in exchange, the method comprising the steps of:
- generating a first RF excitation pulse that selectively excites a first chemical species, wherein the first tip angle increases a signal-to-noise ratio for the first chemical species relative to a second tip angle;
- quantifying the first chemical species based on resonance signals generated in response to the first RF excitation pulse;
- under equilibrium conditions between the first chemical species and a second chemical species, generating a second RF excitation pulse at the second tip angle that excites at least the second chemical species, wherein the second tip angle substantially preserves the total exchange pool of the first chemical species and the second chemical species;
- quantifying the second chemical species based on resonance signals generated in response to the second RF excitation pulse;
- repeating, for a set number of iterations, the steps of generating the first RF excitation pulse, quantifying the first chemical species, generating the second RF excitation pulse, and quantifying the second chemical species;
- and
- obtaining a ratio of the first chemical species and the second chemical species in exchange correcting for the differential effect of the first tip angle and the second tip angle.
4 more elements
A memory structure physically encoding one or more executable routines which, when executed, cause acts to be performed comprising:
- generating a first RF excitation pulse that selectively excites a first chemical species, wherein the first tip angle increases a signal-to-noise ratio for the first chemical species relative to a second tip angle;
- quantifying the first chemical species based on resonance signals generated in response to the first RF excitation pulse;
- under equilibrium conditions between the first chemical species and a second chemical species, generating a second RF excitation pulse at the second tip angle that excites at least the second chemical species, wherein the second tip angle substantially preserves the total exchange pool of the first chemical species and the second chemical species;
- quantifying the second chemical species based on resonance signals generated in response to the second RF excitation pulse;
- repeating, for a set number of iterations, the steps of generating the first RF excitation pulse, quantifying the first chemical species, generating the second RF excitation pulse, and quantifying the second chemical species;
- and
- obtaining a ratio of the first chemical species and the second chemical species in exchange correcting for the differential effect of the first tip angle and the second tip angle.
4 more elements
A magnetic resonance spectroscopy system, comprising:
- a primary field coil configured to generate a primary magnetic field within a volume;
- a radio frequency (RF) coil configured to generate RF pulses;
- one or more control circuits for controlling operation of the primary field coil and the RF coil;
- a memory storing instructions to be executed by the one or more control circuits for implementing a pulse sequence, wherein the pulse sequence, when executed, causes generation of a first RF excitation pulse that selectively excites a first chemical species and that has a first tip angle that increases a signal-to-noise ratio for the first chemical species relative to a second tip angle;
- under equilibrium conditions between the first chemical species and a second chemical species, generation of a second RF excitation pulse at the second tip angle that excites at least the second chemical species;
- repetition, for a set number of iterations, of the acts of generating the first RF excitation pulse and generating the second RF excitation pulse.
3 more elements
Dependencies are inferred from the claim text.